1. Field of the Invention
The present invention relates to a liquid multi-touch sensor and display device and, more particularly, to a high precision multi-touch screen where the interaction medium is liquid, enabling more realistic tactile experience for simulations of synthetic wet environments.
2. Description of the Related Art
Touch-screens are graphical display devices that have the ability to sense where and when a finger from a user is in contact with it. Typically, touch-screens are based on a solid or rigid surface of interaction, such as glass or plastic, usually directly utilizing the display surface of the core CRT or LCD display.
There have been some previous work in enabling touch sensing on more extended surfaces, such as arbitrary walls, tabletops, and some non-planar objects, by, for instance, vibration sensing techniques, and graphical display is served by projecting graphics onto the surface externally using a projector.
Clouds of water-vapor (e.g. fog) have also been utilized as a surface on which to project imagery, including recent innovations such as disclosed in U.S. Pat. No. 6,819,487 (“Fogscreen”), incorporated herein by reference, which describes generating a thin plane of fog in free-space for extended areas. Such a projection screen has interesting properties that are useful for certain applications and since the screen is not rigid or solid, the user may pass his/her hand through the image or walk right through it.
The publication Greene, R., “The Drawing Prism: A Versatile Graphic Input Device,” Proceedings of the 12th Annual Conference on Computer Graphics and Interactive Techniques SIGGRAPH '85, ACM Press, New York, N.Y., 103-110 (1985) (“Greene 1985”), incorporated herein by reference, exploits FTIR on the hypotenuse face of a large right angle prism to sense amorphous contacts on a rigid surface. As described, it utilizes a thin layer of oil or water on the interaction surface to maintain adequate performance due to the variable nature of FTIR response. This layer is not substantial, and is only used to wet the surface of the rigid prism. Furthermore, the prism necessary in even modestly scaled applications is impractically large, heavy, and bulky.